The present invention relates generally to the field of electrical power management, and more particularly to detecting power outages using smartphones.
In geographic areas where the electrical grid is fragile, unscheduled power outages may be a frequent occurrence, which electric utility companies may be slow to detect due to limited sensing. In many cases, an electric utility's primary method for learning about outages is through customer phone calls to the utility's service center. However, customers with landline or voice over Internet (VoIP) phones may be prevented from reporting an outage due to the power failure, and users of mobile phones may not be relied upon to report an outage in a timely fashion, particularly when an outage occurs at night.
Various methods have been employed or proposed for monitoring the quality of an electrical grid and detecting power outages, including using smart meters and/or phasor measurement units (PMUs), and making use of certain smartphone features.
A smart meter is an electronic device that records consumption of electric energy, generally at consumer sites, in set time intervals, and communicates that information periodically to a utility for monitoring and billing. Smart meters enable two-way communication between the meter and the central system. Smart meters may employ real-time or near real-time sensors to provide power outage notification and power quality monitoring. However, smart meters are costly and their deployment is limited in many locales. Moreover, they may themselves rely on the power grid for communicating, making them susceptible to grid failures.
A PMU is a device that measures the electrical waves in an electrical grid using a common time source such as GPS for synchronization. Time synchronization allows synchronized real-time measurements of multiple remote measurement points on the grid. The resulting measurement is known as a synchrophasor. In typical applications, phasor measurement units are sampled from widely dispersed locations in the power system network and synchronized from the common time source. PMUs can be used to assess system conditions, however, PMUs are generally used to measure voltages and currents at generating plants or at critical substations on a power grid, rather than at consumer sites. As with smart meters, PMUs are costly and their deployment is often limited. Moreover, they may rely on phone lines and the power grid for communicating, making them susceptible to grid failures.
Smartphones have also been proposed as a means for detecting and reporting power outages. For example, a smartphone connected to a charger may sense a loss of power without subsequent motion (indicating detachment from the power source) and report this loss, via an installed app, to a central location. Or a smartphone microphone may check for the presence of an audible “hum” generated by AC mains. These methods may be unreliable and impractical under real-world conditions.
A technique that allows power grid operators to quickly detect outages and other disturbances in the electrical grid would be advantageous in that it would reduce the time required to restore reliable power, which would improve the quality of service and increase customer satisfaction, as well as reducing costs.